An intelligent network interface monitors activity states of a client and reports them to a network manager using a single network connection. The network interface monitors interrupts occurring on the client, derives activity states from the interrupts, and logs the activity states on the network interface....http://www.google.de/patents/US6532497?utm_source=gb-gplus-sharePatent US6532497 - Separately powered network interface for reporting the activity states of a network connected client
